Method of and apparatus for manufacture of vacuum tubes



May 24, 1932. J. D. 1.1-: VAN 1,360,105

I METHOD OF AND APPARATUS FOR MANUFACTURE OF, VACUUM TUBES Filed Dec. 26, 1929 awe/Mew Xmm Q). SMNW' Patented May 24, 1932 UNITED STATES PATENT OFFICE.

. JAMES ID. LE VAN, OF MILWAUKEE, "WISCONSIN, ASSIGNOR TO CUTLER-HAMMER, INC.,'

O]? MILWAUKEE, WISCONSIN, A CORPORATION OF DELAWARE METHOD or AND APPARATUS ron MANUFACTURE or VACUUM Teens Application filed December 26, 1929. Serial No. 416,429.

more it is often desirable to heat the tube during exhaustion and such heating vaporizes the mercury and permits some of it to escape as vapor through the exhaust connection so that it is diliicult to provide with certainty the proper amount of mercury in the finished tube. I

The present invention has among its objects to provide for introduction of the mercury or other liquid after exhaustion of the tube and for prior exhaustion of the liquid.

T he accompanying drawing illustrates schematically apparatus by means of which a tube may be conveniently exhausted and subsequently supplied with liquid in accordance with the method constituting part of this invention.

In the drawing. 1 is a tube which is to be exhausted and into which mercury is to be introduced after the proper degree of vacuum is attained. The exhaust opening of the tube is welded or otherwise connected in the usual manner to the exhaust.- main 23 which i.-. provided with an enlargement 4 at the point of connection of the tube. A vessel 5 which is partly filled with mercury 6 is connected by a downwardly inclined conduit 7 with the enlargement l of the exhaust conduit. The.

conduit 7 communicates with vessel 5 at a point slightly above the normal level of the mercury and is preferably welded to the vessel and to the exhaust conduit.

Floating on the mercury is a cylindrical body 8 of glass or other material, of which at least a part 9 is of magnetic material.

The vessel is surrounded by a magnet coil 19 and a battery 1} provides for encrgization of said 0011 upo'ii closure of a switch 12.

The vessel 5 is provided with an opening 13 through which the mercury ma be replenished, said opening being normally closed by the stop cock 14.

\Vith this apparatus it will be: apparent that as the tube 1 is being exhausted the vessel 5 is likewise being exhausted as is also the mercury trapped in the vessel 5. Further, it will be apparent that after exhaustion of the tube and vessel to the desired degree the desired amount of mercury may be transferred to'the tube by forcing the float into the mercury to displace the latter for overflow thereof into conduit 7 This may be accomplished by closure of switch 12 to energize winding which thereupon will act to draw downwardly it's magnetic core 9, thereby raising the level of the mercury for flow of mercury into the tube. The amount of mercury which flows into the tube may be regulated by regulating the strength of the ner or by mounting the coil 10 slidably and moving it downward a given distanceycorresponding to the amount of mercury to be transferred.

\Vhat I claim as new and desire to secure by Letters Patent is: i

. 1. Apparatus for use in the manufacture of vacuum tubes containing a liquid, comprising a liquid containing vessel to be connected to the tube for exhaustion therewith, said vessel having the liquid contained therein trapped against escape during the exhausting operation and having electromagnetic means to eifect transfer of a given amount of said liquid to said tube at will.

2. Apparatus for usein the manufacture or vacuum tubes containing a liquid, comprising a vessel to be connected to the tube for exhaustion therewith, said vessel having an open chamber toreceive a liquid and to trap the same against flowto said tube during the exhausting operation and electromagnetic means associated with said vessel and controllable at will to effect displacement of the liquid forflow of agiven quantitythereof into the tube.

3. Apparatus for use in the manufacture of vacuum tubes containing a liquid, comprising current in the coil 10 in any well known man- 2 1 a 1,sao,1oe

a. vessel to be connected with the tube for exhaustion therewith, said vessel having an open chamber to contain a liquid and to trap the same during exhausting operation and a float within the liquid containing chamber of said vessel having control means whereby it may beactuated at will to displace the liquid for'flow of a given quantity thereof. .7 v

into the tube while in exhausted state.

4. Appa'rtus-fo use inthe manufacture of vacuum tubes containing a liquid, com

prising a vessel to be connected with the tube for exhaustion therewith, said vessel having an open chamber to contain a liquidand to trap the same during exhausting o ration' and an electromagnet having a win ing external'to said vessel and a magnetic core with- 1 in said vessel whereby the liquid in said vessel may be displaced for, flow of a given quan- JnMEs D. LE VANn 

